Download Take Home assignment 3

Take Home assignment 3
1. all organisms need oxygen (02) for ‘cellular respiration’
2. respiration involves 3 phases – breathing, gas transport and gas exchange with the
cells.
3. gases are exchanged between body fluids and the external environment by the process
of osmosis
4. animals that respire through their skin have a moist skin and a close association with
their blood
5. earthworms, insects and vertebrates have a close association between their respiratory
tracts/surface and their blood
6. the respiratory surfaces (alveoli, gill filaments, etc…) have stratified epithelium
(many layers of epithelium)
7. vertebrates have gills or lungs because their total respiratory surface area is greater
than their total body surface area.
8. warm water and fresh water have a greater percentage of dissolved oxygen
9. because of buoyancy in water (floating of gills in water), gills are developed as
infoldings, just like terrestrial vertebrates
10. animals that respire through gills and skin cannot live in dry environments because
they will lost moisture by evaporation
11. counter current exchange refers to flow of fluids in the same direction

21% of the air in the atmosphere is oxygen.
12. more than 5% of the atmospheric oxygen is found dissolved in water and all of the
dissolved oxygen is used by the gills
13. muscle contractions help blood circulation and also respiration in animals
14. an insect in flight consumes twice the amount of oxygen it does at rest
15. the alveoli are sac like structures found in bird lungs
16. the muscular diaphragm together with the muscles of the ribs help expand the rib cage
during respiration. This causes a higher (positive) pressure in the lungs which helps in
respiration
17. the total respiratory surface of a human (100m2) is the same as the body surface of a
human
18. cilia lining the trachea and bronchii keeps the surface moist and helps trap particles
19. the larynx and the pharynx area always open together (at the same time)
20. emphysema is found in gills of fishes

the volume of air in each breath is called tidal volume
21. vital capacity is the maximum amount of air that we can breathe in or out during
forced breathing. This volume is 500ml
22. during forced respiration all the air in the lungs (alveoli)is emptied
23. birds have a residual volume of air at the end of each respiration due to which they
can extract more air than mammals
24. ventilation refers fish passing water over gills or other vertebrates passing air into
their lungs
25. breathing rate is stimulated/triggered by the amount of oxygen dissolved in the blood
26. fishes have a completely separated systemic and pulmonary circuit (compare fig 23.3
A, B and C)
27. iron in hemoglobin is important for transporting the dissolved gasses
28. ectotherms are animals that get their body heat from the environment
29. different types of integument (fur, scales, feathers) and subcutaneous fat provide
convection for the body
30. osmoregulation refers to maintaining a stable concentration of ions in the body fluids
compared to the outside environment
31. the gills of fish are used for gas exchange, but also exchange salts or water with their
environment due to the process of diffusion
32. a freshwater fish loses salts and water through its gills, but gains it by drinking water
33. terrestrial animals do not excrete ammonia, only because ammonia is very toxic
34. on a cold day your body produces dilute urine because the concentration of body
fluids increases
35. liver is responsible for many homeostatic functions including maintenance of blood
sugar levels
36. the liver is the last organ of the body that encounters the digested food
37. Amphibian eggs do not have a shell. This is why they lay their eggs on land.
38. the temperature at the tips of a dolphin’s paddles is the same as the rest of the body
39. water is reabsorbed in the all parts of the nephron by active transport
40. hormones are secreted by some exocrine and endocrine glands
41. pheromones are chemicals that help organs communicate with each other
42. hormones like estrogen have 3 stages in their functioning – reception, signal
transduction pathway and a response
43. epinephrine is a neurotransmitter found in electrical synapses and is also a hormone
44. hormones have specific targets that they reach through the blood circulation
45. melatonin is an important pheromone
46. pancreatic secretions, calcitonin and parathyroid hormone are antagonistic hormones
47. epinephrine, norepinephrine, and glucocorticoids affect blood glucose level like
pancreatic hormones and are controlled by the nervous system
48. the water-salt balance of body fluids affects the secretion of anti-diuretic hormone by
a negative feed back look
49. the thyroid, adrenal cortex, testes and ovaries are regulated by any imbalance in body
fluids
50. glucocorticoids stimulate liver cells to release more glucose
51. pancreatic hormones are secrete from the islets of langerhans in the pancreas
52. prolactin is responsible for milk production in all animals